Airbags screwing with my wd hitch

[Inglysh]

Either the air-ride is screwing up the wd-hitch, the wd-hitch isn't set up properly or both.

I have this style of WD-Hitch CURT Manufacturing - CURT TruTrack Trunnion Bar Weight Distribution System #17500

I am pulling with a 2006 Lexus GX470. Somewhere around a 6500 lb towing cap. I am pulling a 3700# trailer and have 500 lbs in passengers and another 560-800 in fuel & gear depending on where I'm going and for how long.

It is my understanding that when I put the trunnion bars on, they should be levering some weight onto the front of the vehicle, however when I drop the hitch onto the car, I can see that no weight is being transitioned. Worse, is that the leveling suspension raises the back of the vehicle so that if there was any weight being pushed forward, it is all on the back axle.

I am not sure how to fix this. I can disable the air ride but I am not sure how to get it so that it is at the same PSI/ride height every time.

I cannot raise up the back end of the bars, they are positioned as high against the trailer frame as the frame/system will allow.

The dealer sold/installed this, said that it was good & proper however that does not appear at all to be the case.

Should I trash the bags and replace them with springs? The shocks are near gone and need to be replaced anyways.

[Coldfusion]

I installed air bags in my truck and ran into same problem with the bars having no weight on them. I ended up dropping my hitch a notch and raising the bars bracket a notch.
Is there anyway you can air down the bags a bit? I run mine around 20 psi


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[octane]

I'm no expert but I think I read somewhere that you should load up the SUV , let it level, then deactivate the system.


then and only then you can setup the WD hitch, if the bar does not go any higher, raise the tongue of the TT with the jack, until you are able to lift the bars more, if the bars have enough tension, the front and the rear should drop by about the same amount. If the bars don't have enough tension, you probably need to add a washer or two on the wd head to change the angle.

[BCK]

Originally Posted by Inglysh

I cannot raise up the back end of the bars, they are positioned as high against the trailer frame as the frame/system will allow.

That is what the tilt adjustment is for on the head of the hitch. Tilt it away from your vehicle slightly to angle the bars downward do that when tightened they are roughly parallel to the trailer frame.

Can't comment on the airbag system.

[ttavasc]

It sounds like this is a factory auto-leveling air suspension. I have one on my RAM and I can attest to the fact that it took a bit of googling and research in order to understand the best way to approach setting up the wdh. I never did find anything in the RAM towing guide that detailed it. The nature of the system is to always return the vehicle to level regardless of the weight. There are definitely benefits to the system, and I do like mine, but a slightly different approach to set up is needed.

So this is what I've done in order to adjust my hitch and perhaps it will work for you. After the initial set up was complete I've not had to fiddle with it since. Make sure you have a good level place to work.

1. Determine the distance from the ground to the top of the coupler on the trailer with it sitting level or just slightly nose down.

2. Disable the suspension. Then put your hitch on and adjust the top of the ball to be about 1" lower than the measurement in # 1. This will provide a little bit of room for the suspension to adjust without putting the trailer nose-high.

3. Measure the distance between the ground and the front/rear wheel wells to provide a baseline before dropping the trailer on.

4. Drop the trailer on the ball. Don't worry about the sag at this point and don't connect the bars at this time. Take another measurement of the front/rear wheel wells.

5. Connect up the bars and start adjusting. You should be able to see the front wheel well starting to drop back down towards your baseline measurement though you may not be able to return it to the same height as before.

6. After all hitch adjustments are done as best you can, re-engage the suspension. It shouldn't have much work to do at this point but it will eliminate any remaining sag that it may detect on the rear.

One thing that will aid in this effort is a trip or two to the CAT scales to get some accurate axle weights on the TV loaded but without the trailer hooked up, and then again loaded and with the trailer hooked up. This will be the best way to assure that you are returning load back to the front axle. Then you should be good to go.

[Hohenwald48]

I have the same problem with my Armada. Auto level suspension can make set up a bit of a problem. The above posts give a pretty good idea of the procedure. On the Armada, you have 30 seconds after turning on the ignition before the auto level system will respond to raise or lower the rear of the vehicle.

The CAT scale is the real test. If you get the front axle weight the same hitched and unhitched then your set up should be good provided your spring bars are parallel with the tongue. Auto level has almost no impact on front axle loading. All of that is due to spring bar setting.

[BJR]

Originally Posted by octane

I'm no expert but I think I read somewhere that you should load up the SUV , let it level, then deactivate the system.


then and only then you can setup the WD hitch, if the bar does not go any higher, raise the tongue of the TT with the jack, until you are able to lift the bars more, if the bars have enough tension, the front and the rear should drop by about the same amount. If the bars don't have enough tension, you probably need to add a washer or two on the wd head to change the angle.

Yes, the Curt instructions state to disable airbags, etc, prior to configuring the hitch.

As for the angle, this hitch has a pin adjustment for angle that works in the same way as adding washers. Measure the height of your front fender with the vehicle disconnected. Hook up the hitch and re-measure the front fender - if it's not roughly the same measurement (higher than original) then set the tilt pin to the 2nd spot and re-measure. Repeat until the front fender is about where you started. The manual says to connect the ball and raise the hitch 3" as a good starting point for where your bar brackets should be. That did not work for me - I had to do that then lower hitch to the #3 position.

What I found with mine is that putting more weight on the front actually raised the hitch height on the camper. The back end still sags about 3" for me, but so far the ride is OK.

[olyelr]

Like a few others have stated, you need to set up your WD hitch with the auto-level system DISABLED. Once the hitch is properly setup, then turn the auto leveling system back on and let it do it's thing.

My wifes Yukon has the auto level suspension and it works absolutely wonderfully. It towed our 28BHBE around like a champ.

You just have to make sure your hitch is properly setup with the air system off.

[Inglysh]

Thanks for the help everyone. Really appreciate it.
Looks like I have a bit of work ahead of me to get this done right.